-Combine ground almonds, coconut, polenta, baking powder and lemon rind, and set aside. Using electric mixer beat butter and sugar until pale and fluffy.
-Add eggs one at a time, beating well after each. Fold in dry ingredients and lemon juice until just combined. Pour mix into greased and lined 9-inch/24-centimeter round cake tin (not springform) and bake at 325°F/160°C for one hour or until golden and just coming away from the side of the tin.
-Meanwhile, make the lemon glaze by heating the lemon juice and sugar gently, until the sugar is just dissolved.
-Remove from the oven and cool in the tin. Run a knife around the edge of the cake to loosen. Pour on lemon glaze while cake is still warm.
-Allow to cool completely in tin before turning on to a plate, as the cake falls apart easily while warm.
-Spread the lemon icing over the cake when cooled completely. (You can make the icing more like a loose glaze by slightly reducing the amount of icing sugar.)